If you receive such messages on WhatsApp then delete it immediately, these are Fake / Fraud / Scam messages which are designed to trap you. Also, inform the person who sent you this message.

If you click on the link, it will take you to a fake website: http://ksa-freemobile.blogspot.com/?1

If you proceed further, it will ask you about your network (STC/Mobily/Zain).

Upon choosing the network, it will ask about how much credit you need.

Upon choosing the credit, it will ask if you have registered before.

No matter what option you choose, it will ask you to enter your mobile number. So here you are providing them with your mobile number which they don't have.

Upon entering that, it will ask you to share this message with 30 people or groups on WhatsApp to receive your credit. There are also fake comments shown from fake profiles.

So the scammer has got your mobile number and now he will get the mobile numbers of your contacts. They also know that you use this number on WhatsApp. Later on, these numbers can be used for phishing attacks, frauds, advertisements, etc.If you are not aware of phishing attacks then you can read on this link: "How to Spot a Phish (Phishing)" Infographic - PhishMeThis scammer has many fake websites: